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' UNITED STATES PATENT OFFIcE.

JOHN B. CUMMINGS, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE AMERICAN PRESSASSOCIATION, OF SAME PLACE.

BACKING ELECTROTYPE-SHELLS.

SPECIFICATION forming part of Letters Patent No. 375,869, dated January3, 1888.

Application filed June 23, 1886. Serial No. 206.010.

To all whom, it may concern.-

Be it known that I, JOHN R. CUMMINGS, a citizen of the United States,residing at Ohicago, in the county of Cook and State of Illinois, haveinvented certain new and useful Improvements in the Process of BackingElect-rotypeShells; and I do hereby declare the following to be a full,clear, and exact description of the invention, such as will enableothers skilled in theart to which it appertains to make and use thesame.

My invent-ion relates to the process of backing electrotypeshells; andit consists in giving to such shells a backing in a manner that willleave the shell as thin and pliable as when unbackcd.

In the usual process of backing an electrotype shell the shell is firsttinned by the application of a soldering-fluid and tin-foil, for thepurpose of making the metal adhere, and then quite a thick backing oflcad,or whatis known as electrotype metal, is applied by melting on orpouring on the molten metal to the back of the plate until it is aneighth of an inch thick, or more, and a stiff heavy plate is produced.Now the end desired to be attained is the successfulfilling of the cavities of the letters without increasing the thickness of the shell-thatis, to fill the cavities of the letters up to the level of the generalunder surface of the shell, which cannot be accomplished by the ordinaryprocess.

My method consists in taking the shell after the tinning step andapplying to it a backing, either by dipping it into a kettle .of meltedlead or other suitable material, or pouring the molten metal upon theshell, then at once scraping off the bottom (no metal adhering to itsface) with a rule having a straight edge, or other equivalent device,whereby a perfectly smooth even surface is produced, and no more metalis left on the shell than sufiices to fill the depressions and renderthe back smooth; or the filling may be applied without tinning byputting the soldering-fluid on the copper and then proceeding asdescribed; but there are objections to this method.

The importance of this method of filling will I (No specimens.)

be appreciated when itis known thatby the old method several expensivemachines and appliances are requiredviz., backing-pan and table;saw-table for sawing off the margin and for sawing columns apart;atrimmerfor trimming margins close to letters; a roughing-machine tomake plate ready for shaving, and a shavjug-machine to shave plate toexact thickness, which machines and appliances are expensive, besidesrequiring a number of men to operate them. By the old method, also, theplates require to pass through the hands of a finisher to bestraightened and corrected, requiring a skilled laborer, which processis saved by mymethod. By the old method, also, the plate must be sothick as to be stiff enough to withstand the tendency of the shaver tocrook it, which requires a considerable thickness of metal and aconsequent large consumption. By the old method, also, if a column ofplate is to be cut into pieces, as is usually necessary in making upnewspaper-forms, it must be done with a saw, whereas a plate of this description may be cut with scissors between the lines almost as easily aspaper.

The process is performed with greatrapidity, and shells thus backed areas thin and pliable, practically, as before backing, the weight havingincreased only about two ounces per column of twenty inches in length.At the same time shells backed in this way are quite as strong andpermanent as when backed in the old way.

\Vhat I claim as my invention is The method of backing an electrotypeshell,

consisting of applying molten metal thereto, and then at once scrapingoff the back of the shell with a suitable device-such as a rule with astraight edge-whereby all superfluous metal is removed and aperfectly-finished, light, pliable shell is produced without furtheroperation, substantially as described.

latestimony whereof I affix my signature in presence of two witnesses.

JOHN B. CUMMINGS.

Witnesses:

EDWD. G. PAULING, HORACE WHITE.

